diff --git a/src/bootstrap_gui.cpp b/src/bootstrap_gui.cpp
--- a/src/bootstrap_gui.cpp
+++ b/src/bootstrap_gui.cpp
@@ -385,9 +385,9 @@ bool HandleBootstrap()
 	 * This way the mauve and gray colours work and we can show the user interface. */
 	GfxInitPalettes();
 	static const int offsets[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x80, 0, 0, 0, 0x04, 0x08 };
-	for (uint i = 0; i != 16; i++) {
+	for (Colours i = COLOUR_BEGIN; i != COLOUR_END; i++) {
 		for (int j = 0; j < 8; j++) {
-			_colour_gradient[i][j] = offsets[i] + j;
+			SetColourGradient(i, j, offsets[i] + j);
 		}
 	}